1. Field of the Invention
The present invention is generally directed to the field of flow control devices, and, more specifically, to an integrated plug/choke valve.
2. Description of the Related Art
A choke valve is a throttling device used to reduce the fluid pressure or flow rate in a flow line. Hereinafter the device is referred to as a “choke.” Chokes are commonly used in connection with well drilling and production operations for producing oil or gas, although they have other applications as well.
In many cases, the stream passing through the choke is very erosive. For example, a choke used in a drilling or production operation may be exposed to a high pressure gas stream moving at high velocity and carrying sand particles. In the course of undergoing pressure reduction in passing through the choke, the velocity of the flow stream is increased. This exacerbates the erosional effect of the flow stream. Choke failure due to erosion can lead to very serious problems in controlling well flow or, at a minimum, leads to costly repairs.
Plug valves are currently used to bleed flowlines. This is done by cracking the plug open and allowing high velocity erosive flow to travel through the partially open valve. This leads to the plug valve wearing out very quickly due to erosion of the body. Existing chokes do not achieve zero shut off in a way that can survive high speed erosive flow.
The present invention is directed to an apparatus for solving, or at least reducing the effects of, some or all of the aforementioned problems.